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Article Dans Une Revue Journal of the European Ceramic Society Année : 2013

Influence of iron on the occurrence of primary mullite in kaolin based materials: A semi-quantitative X-ray diffraction study

Résumé

Iron-enriched reference kaolins (KGa-1b, KGa-2 and KF) were used to study the effect of iron on the development of mullite phases during the sintering of kaolin-based materials. Up to 1050 °C, primary mullite formation occurred at earlier temperature within iron-enriched kaolins than in the case of iron-free kaolins. At 1150 °C, the presence of ferric ions tended to promote the transformation of the spinel (γ-Al2O3-like) phase into primary mullite. This action was correlated with an enhancement of the diffusion mechanism of the main constitutive species of the samples (Al, Si). In the range 1300–1400 °C, iron-enriched kaolins exhibited an abnormal grain growth of secondary mullite crystals and a partial reduction of hematite (Fe2O3) into magnetite (Fe3O4). These two iron compounds reacted with mullite and cristobalite, leading to the occurrence of eutectic liquids as expected from phase equilibrium diagrams.

Domaines

Matériaux
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Dates et versions

hal-01116972 , version 1 (16-02-2015)

Identifiants

Citer

Gisèle Laure Lecomte-Nana, Jean-Pierre Bonnet, Nibambin Soro. Influence of iron on the occurrence of primary mullite in kaolin based materials: A semi-quantitative X-ray diffraction study. Journal of the European Ceramic Society, 2013, 33 (4), pp.669-677. ⟨10.1016/j.jeurceramsoc.2012.10.033⟩. ⟨hal-01116972⟩
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